What is a bone marrow biopsy?
In a bone marrow biopsy, a doctor or medical technician removes a small sample of bone marrow from inside bone. The bone is usually taken from the pelvic bone, although occasionally it is taken from the breastbone.
To reach the marrow, a special needle is inserted through the skin and into the bone. The sample is sent to a laboratory and examined under a microscope.
Doctors study the appearance, size and shape of cells in the bone marrow, looking for abnormalities that might indicate disease. They also examine how the cells interact with each other and measure the number of those cells compared to fat and other substances in the sample.
What is bone marrow?
Bone marrow is soft, sponge-like tissue inside the hollow center of larger bones and liquid that looks like blood. Bone marrow produces:
- Red blood cells, which carry oxygen throughout the body
- White blood cells, which are part of the immune system that protects the body from foreign invaders and infectious diseases
- Platelets, which form clots to stop bleeding when blood vessels are damaged
The liquid component of bone marrow contains stem cells, which are maturing blood cells, along with vitamins needed for cell production.
When would a doctor order a bone marrow biopsy?
Doctors might order a bone marrow biopsy if they notice an abnormal number of red or white blood cells or platelets in a blood sample.
- A low white-blood-cell count might be linked with a viral infection, since white blood cells help fight viruses. Also, a fever of unknown origin or weakened immune system can indicate a shortage of white blood cells.
- A lack of red blood cells means that a patient has anemia, which can cause tiredness and weakness. The body doesn’t have enough red blood cells to circulate oxygen adequately through the body.
A bone marrow biopsy can help determine if a disease, like cancer, is preventing the bone marrow from creating blood cells. In some cases, doctors can spot changes to blood cells in bone marrow before they can see the changes in blood samples.
Periodic bone marrow biopsies are done in patients already undergoing cancer treatments to see if their bone marrow is working normally again.
What conditions and diseases are diagnosed with a bone marrow biopsy?
Doctors use a bone marrow biopsy to diagnose and help find the cause of:
- Leukemia, which is cancer of the blood cells. The disease originates in bone marrow and results in too much production of one type of blood cell.
- Leukopenia or leukocytosis, a condition marked by too many or too few white blood cells.
- Multiple myeloma, which causes bone damage. Diseased cells are found in the bone or bone marrow.
- Anemia, a lack of enough red blood cells that carry oxygen throughout the body.
- Aplastic anemia, a condition that harms the marrow’s ability to produce an adequate number of each blood cell type.
- Polycythemia, an abnormal increase in blood cell production in the bone marrow.
- Myelofibrosis, a disorder involving fibrous scar tissue replacing bone marrow. This leads to changes in the shape and number of red blood cells.
- Thrombocythemia, in which the bone marrow creates too many platelets.
- Myelodysplastic syndrome, a bone marrow disorder in which stem cells don’t mature properly.
- Lymphoma, breast cancer or lung cancer, which are diseases that start elsewhere in the body but can spread to bone marrow.
A bone marrow biopsy can also detect abnormalities in chromosomes and vitamin deficiencies, which can trigger the bone marrow to produce red blood cells that are misshaped or too large.
How is a bone marrow biopsy performed?
The test can be done in the office or hospital. Typically the steps are as follows:
- The patient is awake and lies on their side.
- If necessary, the doctor or medical technician administers medication to help the patient relax.
- The skin is cleaned with antiseptic.
- A numbing medication is injected through the skin to the bone surface.
- The biopsy needle is inserted into the bone, either by hand or with the help of an electric device. The center of the needle is removed, and the liquid samples are then collected from the hollowed-out needle. The liquid samples are called the bone marrow aspiration.
- The needle is then advanced again to capture a small piece of the sponge-like tissue. The sponge-like sample is called the core biopsy.
- The needle with sample is taken out, and pressure is applied to the patient’s skin to stop any bleeding. A bandage is placed over the wound.
In most cases, the patient goes home the same day, although if sedation was used during the biopsy, someone else will have to drive. The wound needs to stay dry and covered for about 24 hours.
What is the procedure like for the patient?
The patient will feel a sharp sting when the numbing medication is injected, and might feel a brief, dull pain when the biopsy needle is inserted. Unfortunately, the bone itself can’t be numbed. The patient might feel pressure, pushing and pulling, and that can cause discomfort. After the test, the patient might experience slight bone pain or discomfort for about a week. The doctor may advise taking a nonprescription pain reliever.
What should the patient tell the doctor before a bone marrow biopsy?
The provider should have a list of all the patient’s medications and supplements and if the patient is allergic to any medications. The provider should also know if the patient has any bleeding problems or disorders (such as hemophilia), is on a blood thinner, or is pregnant.
Results and Follow-Up
Are there risks to a bone marrow biopsy?
Complications are rare. The patient should call the doctor’s office if they experience excessive bleeding from the test site, excessive redness (especially if it spreads), fever or pain that worsens.
Can bone marrow samples be used for other tests?
Yes. Other tests in which bone marrow samples can be used include:
- Florescence in situ hybridization, or FISH, which can detect changes to chromosomes, or genetic abnormalities, in blood cancer cells. Typical under-the-microscope blood tests can miss these changes.
- Flow cytometry, which studies blood and blood marrow cells to learn if a high white blood cell count is due to blood cancer. The test, using a laser beam, measures the size and shape of blood cells and determines their classifications. The test also looks for abnormalities in strands of DNA inside bone.
- Immunophenotyping, which can identify a specific type of cell in a blood, bone marrow or lymph node sample. For example, the test can tell the difference between normal lymphocytes –white blood cells that are part of the immune system – and those with leukemia.
- Karyotype tests, which by using a map of the 46 human chromosomes, can find and evaluate any alterations to the chromosome pattern, size, shape and number.
- Polymerase chain reaction, which can locate any remaining blood cancer cells not found through the FISH test.
- Cytogenetic analysis, which can identify chromosome abnormalities that might signal multiple myeloma.